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MI - secondary prevention
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Exam Tips
- In UK finals/OSCEs, frame post-MI care as: cardiac rehab + DAPT plan + high-intensity statin + ACEi/ARB + beta-blocker + risk-factor modification + complication surveillance.
- Always state antiplatelet duration explicitly (typically 12 months DAPT after ACS unless bleeding risk mandates shorter specialist-led strategy, then lifelong single antiplatelet).
- If a patient develops cough on an ACE inhibitor after MI, switch to an ARB rather than stopping RAAS blockade altogether.
- Mention safety checks examiners expect: renal function/potassium after ACEi or ARB titration, LFTs for statin, and bleeding review for DAPT.
- Do not recommend omega-3 capsules, antioxidant vitamins, folic acid, or beta-carotene for recurrent MI prevention; this is a common SBA trap.
- Include psychosocial recovery (depression screening, return to work, adherence barriers such as transport to rehab) as part of holistic secondary prevention.
Definition
Myocardial infarction (MI) secondary prevention is the long-term, structured management given after STEMI or NSTEMI to reduce recurrent coronary events, heart failure, stroke, and death. It combines cardiac rehabilitation, intensive risk-factor modification, and evidence-based medicines (antiplatelets, lipid-lowering therapy, RAAS blockade, and usually beta-blockade) with ongoing monitoring for complications and treatment adverse effects.
Pathophysiology
Most MIs follow rupture or erosion of an atherosclerotic coronary plaque, causing thrombus formation and downstream myocyte necrosis. After the acute event, infarct healing (inflammation -> granulation tissue -> scar) and neurohormonal activation (sympathetic system and renin-angiotensin-aldosterone system) drive adverse left-ventricular remodelling, recurrent ischaemia risk, arrhythmia substrate, and progressive heart failure; secondary prevention targets these pathways and residual atherothrombotic risk. See Figure: infarct healing phases and LV remodelling timeline; see also Figure: ECG territorial lead changes (STEMI vs NSTEMI spectrum).
Risk Factors
- Hypertension
- Current smoking
- Atherogenic dyslipidaemia (high non-HDL cholesterol, low HDL)
- Diabetes mellitus, impaired glucose tolerance, and metabolic syndrome
- Physical inactivity and sedentary behaviour
- Overweight/obesity
- Unhealthy diet
- Excess alcohol intake
- Older age
- Male sex (earlier event age on average)
- Family history of premature cardiovascular disease in a first-degree relative
- South Asian ethnicity and other higher-risk ethnic backgrounds
- Chronic kidney disease
- Obstructive sleep apnoea
- Chronic inflammatory disease (for example rheumatoid arthritis, SLE)
- Familial hypercholesterolaemia
- Atrial fibrillation
- COPD
- Mental health disorders (depression, anxiety, psychotic illness)
- Cocaine use
- Air pollution exposure
- Recent influenza infection
Clinical Features
Symptoms
- Often asymptomatic at routine follow-up if recovery is uncomplicated
- Recurrent exertional chest pain or chest tightness (possible angina/re-infarction)
- Breathlessness, orthopnoea, or reduced exercise tolerance (possible LV dysfunction/heart failure)
- Palpitations, presyncope, or syncope (possible arrhythmia)
- Medication adverse effects: dizziness/hypotension, cough (ACE inhibitor), myalgia (statin), bruising/bleeding (antiplatelets)
- Low mood, anxiety, poor sleep, reduced confidence returning to activity/work
Signs
- Raised blood pressure or persistent tachycardia if risk factors uncontrolled
- Signs of heart failure (bibasal crackles, elevated JVP, peripheral oedema, displaced apex)
- New pansystolic murmur (consider acute MR from papillary muscle dysfunction if early post-MI)
- Irregular pulse or brady/tachyarrhythmia
- Evidence of bleeding on antithrombotics (pallor, melaena history, bruising)
- Central adiposity and deconditioning
Investigations
12-lead ECG:May show prior infarct changes (Q waves, T-wave inversion) or new ischaemic/arrhythmic changes if recurrent symptoms
Echocardiography (LV function assessment):Regional wall-motion abnormality; reduced LVEF predicts higher HF and mortality risk
Lipid profile (non-fasting acceptable):Used to assess response to high-intensity statin; target is substantial LDL-C/non-HDL reduction from baseline
Renal function and electrolytes (U&Es, creatinine, potassium):Monitors ACE inhibitor/ARB safety and dose titration; hyperkalaemia or creatinine rise may require adjustment
Liver enzymes (ALT/AST):Baseline and follow-up safety monitoring for statin therapy
HbA1c (or fasting glucose):Detects diabetes or post-MI dysglycaemia; annual surveillance recommended if hyperglycaemia occurred during MI admission
Full blood count:Screens for anaemia or occult bleeding risk while on antiplatelet therapy
Blood pressure, BMI/waist, smoking status, alcohol history:Tracks modifiable risk-factor control during structured secondary prevention
Management
Lifestyle Modifications
- Offer and strongly encourage comprehensive cardiac rehabilitation (exercise, education, lifestyle counselling, stress management); use home-based programmes if centre-based rehab is impractical
- Smoking cessation support (behavioural plus pharmacotherapy where suitable)
- Mediterranean-style cardioprotective diet, weight reduction where indicated, and regular physical activity with graded return after specialist advice
- Reduce alcohol intake to UK recommended limits
- Address psychosocial factors: anxiety/depression screening, return-to-work planning, social/welfare support
- Annual influenza vaccination
- Do not recommend omega-3 capsules, antioxidant vitamins (E/C), folic acid, or beta-carotene supplements for preventing recurrent MI
Pharmacological Treatment
Antiplatelet therapy (DAPT then single antiplatelet)
- Aspirin 75 mg once daily lifelong
- Ticagrelor 90 mg twice daily for up to 12 months with aspirin
- Alternative P2Y12 options when appropriate: clopidogrel 75 mg once daily or prasugrel 10 mg once daily (after 60 mg loading in PCI pathways)
Balance ischaemic benefit against bleeding risk at follow-up. Avoid prasugrel in prior stroke/TIA; use caution if age >=75 years or weight <60 kg. Consider gastroprotection (for example omeprazole) in high GI-bleed risk; avoid stopping DAPT early unless specialist-directed because of stent-thrombosis risk.
Lipid lowering
- Atorvastatin 80 mg at night (or once daily)
- Add ezetimibe 10 mg once daily if cholesterol remains above target despite maximal tolerated statin
Check baseline and follow-up liver enzymes; counsel about myalgia and rare rhabdomyolysis. Avoid in pregnancy and severe active liver disease.
RAAS blockade
- Ramipril 2.5 mg once or twice daily initially, titrating to 10 mg/day in divided or single dose as tolerated
- If ACE-inhibitor intolerance (for example troublesome cough): candesartan 4 mg once daily, titrating up (commonly toward 32 mg once daily)
Particularly important with LV dysfunction, anterior MI, diabetes, or hypertension. Monitor creatinine and potassium after initiation and dose changes; caution in bilateral renal artery stenosis, hyperkalaemia, and hypotension. ACE inhibitors are contraindicated in pregnancy.
Beta-blocker
- Bisoprolol 1.25 mg once daily initially, titrating gradually (commonly up to 10 mg once daily)
- Alternative: carvedilol 3.125 mg twice daily, titrating as tolerated
Useful post-MI, especially with reduced LVEF or arrhythmia risk. Contraindications/cautions: severe bradycardia, high-grade AV block without pacing, cardiogenic shock, and uncontrolled asthma/bronchospasm. Titrate to pulse, BP, and symptoms.
Adjunctive cardiometabolic risk management
- Antihypertensives to BP target per UK hypertension guidance
- Glucose-lowering therapy if diabetes is confirmed (agent choice individualised to CVD profile)
Optimise all reversible risk factors; coordinate with diabetes/hypertension pathways.
Surgical / Interventional
- Cardiology review for further coronary revascularisation where indicated (repeat PCI or CABG based on anatomy/symptoms/ischaemia burden)
- Device therapy in selected high-risk patients after recovery (for example ICD for persistent severe LV systolic dysfunction under specialist guidance)
Complications
- Re-infarction or infarct extension
- Angina recurrence
- Left ventricular dysfunction and chronic heart failure
- Cardiogenic shock (early severe cases)
- Mechanical complications: ventricular septal rupture, papillary muscle rupture causing acute MR, free-wall rupture, LV aneurysm
- Arrhythmias (AF, AV block, VT/VF, sinus bradycardia/tachycardia)
- LV thrombus and systemic embolism; venous thromboembolism
- In-stent thrombosis (especially with premature DAPT interruption)
- Pericardial syndromes (early pericarditis, Dressler syndrome, pericardial effusion)
- Major bleeding (including GI or intracranial) related to antithrombotic therapy
- Depression, anxiety, reduced quality of life, sudden cardiac death
Prognosis
Outcomes after MI in the UK have improved markedly with rapid reperfusion and modern secondary prevention, and most patients now survive the index event. Prognosis is worse with larger infarct size, delayed reperfusion, anterior MI, reduced LVEF, renal disease, diabetes, COPD, frailty, older age, female sex, and poor adherence to medicines/rehabilitation. Early readmission remains common (roughly one in eight within 30 days), often due to recurrent ischaemia or heart failure.
Sources & References
💊BNF Drug References(6)
- Aspirin[management.pharmacological]
- Atorvastatin[management.pharmacological]
- Azithromycin[management.pharmacological]
- Ciprofloxacin[management.pharmacological]
- Flucloxacillin[management.pharmacological]
- Rifampicin[management.pharmacological]
✅NICE Guidelines(1)
- MI - secondary prevention[overview]
📖Textbook References(20)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1420)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1033, 1034)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1033, 1034)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1041, 1042)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1844)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 480)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1834)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 301, 302)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1421)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1037)[context]
- Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 81)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 135)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 228)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 225)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 225)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 705)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 326, 327)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 335)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 341, 342)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 341, 342)[context]